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Unblock-Tpm

Updated: October 29, 2012

Applies To: Windows Server 2012

Unblock-Tpm

Resets a TPM lockout.

Syntax

Parameter Set: Owner Auth
Unblock-Tpm [[-OwnerAuthorization] <String> ] [ <CommonParameters>]

Parameter Set: File
Unblock-Tpm -File <String> [ <CommonParameters>]




Detailed Description

The Unblock-Tpm cmdlet resets a Trusted Platform Module (TPM) lockout. TPM locks itself to prevent tampering or attack. This is called a lockout. To end a TPM lockout, you must provide a valid owner authorization value. You can enter an owner authorization value or specify a file that contains the value. If you do not provide a value, the cmdlet attempts to use a value stored in the registry.

For more information on TPM, see the Trusted Platform Module Technology Overview in the Technet library at http://technet.microsoft.com/en-us/library/jj131725.aspx.

Parameters

-File<String>

Specifies a file that contains the current owner authorization value for the TPM. You can use the TPM Management Console to create this file.


Aliases

none

Required?

true

Position?

named

Default Value

none

Accept Pipeline Input?

false

Accept Wildcard Characters?

false

-OwnerAuthorization<String>

Specifies the current owner authorization value for the TPM.


Aliases

none

Required?

false

Position?

2

Default Value

none

Accept Pipeline Input?

true (ByValue)

Accept Wildcard Characters?

false

<CommonParameters>

This cmdlet supports the common parameters: -Verbose, -Debug, -ErrorAction, -ErrorVariable, -OutBuffer, and -OutVariable. For more information, see    about_CommonParameters.

Outputs

The output type is the type of the objects that the cmdlet emits.

  • TpmObject

    A TpmObject object contains the following information:

    -- TpmReady. Whether a TPM complies with Windows Server® 2012 standards.
    -- TpmPresent. Whether there is a TMP on the current computer.
    -- ManagedAuthLevel. The level at which the operating system manages the owner authorization. Possible values are Legacy, Balanced, and Full.
    -- OwnerClearDisabled. Whether TPM can be reset. If this value is True, the TPM cannot be reset through the operating system by using the owner authorization value. If this value is False, the TPM can be reset through the operating system.
    -- AutoProvisioning. Whether the computer can use auto-provisioning. Possible values are NotDefined, Enabled, Disabled, and DisabledForNextBoot.
    -- LockedOut. Whether a TPM is locked out.
    -- SelfTest. Information returned by a test that TPM runs.


Notes

  • Be sure to understand the protection logic TPM uses. The TPM allows at least one attempt to reset the TPM lockout by using the owner authorization value. For more information, see the Reset the TPM Lockout topic in the Technet library at http://technet.microsoft.com/en-us/library/dd851452.aspx.

Examples

 

This command resets a TPM lockout. The command specifies the owner authorization value vjnuW6rToM41os3xxEpjLdIW2gA=.


PS C:\> Unblock-Tpm -OwnerAuthorization"vjnuW6rToM41os3xxEpjLdIW2gA="

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